hi... you have progesterone
implant for the contraception
... you have intermittent bleeding and mastalgia and weekness..
this is the common side effect with progesterone which causes intermittent bleeding, fluid retention and mastalgia...
did the nexplanon was inserted immediately after the implanon
was removed?.. if not then check for possibility of pregnancy
.. get one urine pregnancy test and serum HCG levels.. see your obstetrician in any case...
nexplanon will not interfere with the pregnancy tests..
all the very best..